WikiLeaks founder Julian Assange yesterday signed a deal to publish his autobiography in Britain with the Edinburgh-based publisher Canongate Books.

Jamie Byng, Canongate's founder, will publish the book next year. Knopf, a division of Random House, has the US publication rights.

The house expects Assange to finish his manuscript by March – if he resists extradition to Sweden, where he is wanted for questioning about sexual assault allegations.

Canongate refused to officially comment, but Byng said on Twitter: "Word travels fast. The cat is out of the bag and via a Spaniard." Byng was referring to Claudio Lopez, head of Random House's Spanish-language division Monadori, who mentioned the deal on Monday, also on Twitter.

The deal was reportedly brokered by Caroline Michel of literary agents Peters, Fraser, and Dunlop (PFD). "It's a big risk," said The Bookseller's editor-in-chief Neill Denny. "This represents a high-profile gamble by Canongate because it assumes that Assange is cleared of all charges, but yes, it will be a fascinating book.

"It will tell the tale of the brains behind some of the biggest journalistic stories of the decade."

Denny said Canongate would hope such a book would sell between 50,000 and 80,000 copies in hardback. "There will be a market in selling this mysterious figure to the public," he added. "Those behind brokering such a deal must be certain he will not be convicted."

The memoir will follow the revelations of Assange's former Wikileaks deputy Daniel Domscheit-Berg, whose book Inside WikiLeaks: My Time at the World's Most Dangerous Website will be published by German publisher Econ Verlag on 27 January.

Texas-based Global Language Monitor said yesterday that WikiLeaks has met the criteria of reach, depth and breadth to be considered a proper word.

GLM research shows the word first appearing in global media in 2006. It has now been cited more than 300 million times. The group's standards include a minimum of 25,000 citations in English-speaking media.

* Apple is reported to have removed an application that lets iPhone and iPad owners browse the WikiLeaks archive from its App Store.